A classic transaction securing technique consists of authenticating the electronic card involved in the transaction by means of a personal code known to the carrier of said card, for example a 4-digit code. Such a technique is not however completely reliable, insofar as said code can be discovered, for example by observation when the code is entered at the time of a transaction, or by searching by means of a program, in order to use the cart stolen from its carrier.
To overcome these disadvantages, there are techniques enabling the safety of transactions to be reinforced, by adding in particular a phase of biometric authentication of the card carrier, for example by obtaining fingerprints, by voice recognition, and so on.
However, these techniques are expensive to use, due to the implementation of a biometric sensor, they are less user-friendly, as the user must provide a biometric fingerprint, and they make the transactions more complex and in particular more time-consuming.